Patrick Rudolph e4f9d5c70a nb/intel/sandybridge: Start PEG link training
Issue observed:
The PCIe Root port shows up in GNU/Linux but no PCIe device
is being detected.

Test system:
* Gigabyte GA-B75M-D3H (Intel Pentium CPU G2130)
* Lenovo T530 (Intel Core i5-3320M CPU)

Problem description:
The PEG Root port link training on Ivy Bridge needs to be manually started.

Problem solution:
The bits are set in early_init to meet PCIe reset timeout of 100msec.
The bits should be set in PCI device enable function, but this causes the
PCI enumeration to not detect the card, as it's still booting. Adding
a fixed delay of 100msec resolves this problem, but this would
increase boot time.
Read the PCI base revision mask to make sure it's any IvyBridge CPU.
Don't run the code on MRC path as it has its own PEG initilization code.

Tested with:
* Nvidia NVS 5400M (PCIe2)
* ATI Radeon HD4780 (PCIe2)
* Nvidia GeForce 8600 GT (PCIe1)

Untested:
* PCIe3 devices

Final test results:
The PEG device shows up under GNU/Linux and can be used without issues.

Change-Id: Id8cfc43e5c4630b0ac217d98bb857c3308e6015b
Signed-off-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-on: https://review.coreboot.org/11917
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
2016-02-18 01:40:07 +01:00
2012-11-01 23:13:39 +01:00
2006-08-12 22:03:36 +00:00

-------------------------------------------------------------------------------
coreboot README
-------------------------------------------------------------------------------

coreboot is a Free Software project aimed at replacing the proprietary BIOS
(firmware) found in most computers.  coreboot performs a little bit of
hardware initialization and then executes additional boot logic, called a
payload.

With the separation of hardware initialization and later boot logic,
coreboot can scale from specialized applications that run directly
firmware, run operating systems in flash, load custom
bootloaders, or implement firmware standards, like PC BIOS services or
UEFI. This allows for systems to only include the features necessary
in the target application, reducing the amount of code and flash space
required.

coreboot was formerly known as LinuxBIOS.


Payloads
--------

After the basic initialization of the hardware has been performed, any
desired "payload" can be started by coreboot.

See http://www.coreboot.org/Payloads for a list of supported payloads.


Supported Hardware
------------------

coreboot supports a wide range of chipsets, devices, and mainboards.

For details please consult:

 * http://www.coreboot.org/Supported_Motherboards
 * http://www.coreboot.org/Supported_Chipsets_and_Devices


Build Requirements
------------------

 * make
 * gcc / g++
   Because Linux distribution compilers tend to use lots of patches. coreboot
   does lots of "unusual" things in its build system, some of which break due
   to those patches, sometimes by gcc aborting, sometimes - and that's worse -
   by generating broken object code.
   Two options: use our toolchain (eg. make crosstools-i386) or enable the
   ANY_TOOLCHAIN Kconfig option if you're feeling lucky (no support in this
   case).
 * iasl (for targets with ACPI support)

Optional:

 * doxygen (for generating/viewing documentation)
 * gdb (for better debugging facilities on some targets)
 * ncurses (for 'make menuconfig' and 'make nconfig')
 * flex and bison (for regenerating parsers)


Building coreboot
-----------------

Please consult http://www.coreboot.org/Build_HOWTO for details.


Testing coreboot Without Modifying Your Hardware
------------------------------------------------

If you want to test coreboot without any risks before you really decide
to use it on your hardware, you can use the QEMU system emulator to run
coreboot virtually in QEMU.

Please see http://www.coreboot.org/QEMU for details.


Website and Mailing List
------------------------

Further details on the project, a FAQ, many HOWTOs, news, development
guidelines and more can be found on the coreboot website:

  http://www.coreboot.org

You can contact us directly on the coreboot mailing list:

  http://www.coreboot.org/Mailinglist


Copyright and License
---------------------

The copyright on coreboot is owned by quite a large number of individual
developers and companies. Please check the individual source files for details.

coreboot is licensed under the terms of the GNU General Public License (GPL).
Some files are licensed under the "GPL (version 2, or any later version)",
and some files are licensed under the "GPL, version 2". For some parts, which
were derived from other projects, other (GPL-compatible) licenses may apply.
Please check the individual source files for details.

This makes the resulting coreboot images licensed under the GPL, version 2.

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